Cabin pressure control instrument



Feb. 23, 1954 B. E. DEL MAR CABIN PRESSURE CONTROL INSTRUMENT Filed May 21, 1952 Z 4 6 8'01214/6/8 2O 22 24- 2628 3032 34363840 4Z77f005 fleas/W0 75%;-

v INVEN TOR. a? 551 M42 j one end of a control arm 2|.

f ment sealed as is also the opening in which it is mounted. 'A lead 29 interconnects the control material which is removably mounted within the case through the opening hermetically sealed by the closure element The frame |2, as will be seen, forms a support element carrying the operative members of the instrument and permits removal of the operative elements from the case for repair merely by sliding the frame I2 out of the case after the closure element H has been removed from the open end thereof.

Th one wall of the case i is formed with a tapped aperture is adapted to receive the one end of a tube or conduit, not shown, but which leads to ambient flight pressure. A hollow spool element 14, carried by the frame l2 and fixed to the interior wall surface of the case It, supports a capsule assembly 15, the interior of which is in communication with the opening |3 through the hollow spool M so that the interior of this capsule assembly is subject to ambient flight pressure.

The wall of the case |l is formed with a second tapped aperture Iii intended to be used to secure one end of a tube or conduit, not shown, leading tocabin absolute pressure. A capsule assembly surface of the case to the end that the interior of the capsule assembly I? communicates with the opening l6 and is therefore subject to cabin absolute pressure.

move in response to changes in flight absolute pressure while the capsule assembly ll will move in response to changes in cabin absolute pressure.

The movable end of the capsule assembly I is pivotally interconnected by a short link 59 to the The intermediate portion of this control arm is pivotally connected by a link 22 to the movable end of the cabin pressure responsive capsule It will thus be seen that the control arm 2| is angularly moved as the capsule assemblies l5 and IT expand and contract in response to changes in the pressures to which they are internally subjected. v

The free end of the control arm 2| carries a contact element 23 which is movable into and out The contact prong 27 forming a part of a connector plug 28 mounted in an opening formed in the closure ele- The connector plug is hermetically arm 2| and a suitable ground '3! through the con- I nector plug 28 as shown.

The connector plug 28 forms a means by which the instrument of the present invention can be electrically interconnected into a control circuit of the cabin pressure regulating system. To illustrate the operation of the instrument, there is illustrated in Figure l a schematic showing of a control circuit with which the instrument can be used. In this system a motor 35, through a suitablegear train not shown, operates a valve 36 9 used to control the rate of air discharge from the through a control relay.4| which, asv shown for coil 43 causes the armature d5 of the relay to move to the left, as viewed in Figure l, and into engagement with a contact 46 against the action of one of a pair of centering springs d? to complete a circuit from the battery 3% through the circuit of the field coil 3?. Energization of this field coil produces such rotation of the motor to drive the valve 36 toward a closing position to decrease the rate of air discharge from the cabin.

Energization of relay coil M causes the armature 55 of the relay to move to the right, as viewed in Figure l, to engage with contact all against the action of the other of the pair of centering springs 41 to complete a circuit from the battery 39 through the circuit of the field coil 38. The completion of this circuit, as should now be under- As the case 16 is evacuated, it .30,

will thus be seen that the capsule assembly !5 will stood, causes the motor to drive the valve 36 in the opposite direction, that is, towards an open position to increase the rate of air discharge from the cabin.

Energization'of the relay ll is in part controlled by pressure responsive means schematically shown at 49. The control means schematically shown at as may comprise any control elements desired which will regulate cabin pressure along some preselected or desired pressure schedule as the aircraft is flown at altitudes at which pres- .surization is desired.

It will be seen that the contact member 21 of the connector plug 28 is electrically connected into the control circuit by a conductor 5| which includes the coil 52 of a relay operated switch 54. It will be seen that the switch 54 is connected into the circuit of relay coil 43 and this switch is normally held in a circuit closing position by a spring 55. As the coil of the relay operating the switch forms a part of the conductor circuit 5|, this coil when energized will open the switch 54 against the action of the spring 55.

Once the switch 54 is'moved to its open circuit position the control means 49 is rendered inopcrative to energize relay coil 43. Thus, if at the time the contact 23 of the control arm 2| moves into engagement with the contact 24 control means 49 isenergizing relay coil 43 and the valve 36 is moving toward closed position, the relay operated switch 54 willbe moved to its open circuit position simultaneously with energization of the coil 44 of the relay 4|. This, as should now be understood, renders control means Gil inoperative to continue to control valve closing relay 43 and the valve will be moved toward open position under the control of the instrument of the present invention.

The particular relationship of the capsules and the manner in which the link means interconnects the capsules with the control arm, together with position of the contact 24, will obviously determine the value of the ratio of pressures which will result in movement of the contact 23 into engagement with the fixed contact 24.

In any event, the ambient flight pressure capsule |5 will in effect pivotally mount the one end ofthe will arcuately move the control arm about the axis established by the pivotal connection bextween'the arm 2| and the link |9. It will thus suretwill bring about an expansion oftthe capsul'e assembly l1: to. move-the control. arm 21:, regardeless. of: the position of: the qapsule-assemblv w, in a clock-wise direction. to, move; contact element reward: contact 24;, The amount-of: angular mouemenbof-the arm/21 to. bringabout. engage: mer t: oi? the contaetsifi: and 2.4 will; thus. depend the ratio: of pressures to.[WhiQhiifihBi'CflDSl-HG afieemblies, are; Subjectfidi,

As: the eapsule. assembliea l5. and; 1'1 are sun: jeet; to and movable: inrresn mse to: changes in amhiene. night 7 pressure. and: cabin; alasolutelnres; sure; the contact 2-3; QfthQ; control; arm; lat will be: moved into: engagement.- with: the-ticontzaotczii whenever the. ratiotor cabinw absolute-.preesureto mbient: fli ht: nnessure: equalswthet preselected ratio.v Thus; the aetionoe therinstrrument: ofathe nresent; invention. effectivelynrevents, the. ratio oft-pressures from, exceedin thelnreselected;ratio for: as soon as; the preselected ratio; iszexceedecl. theinstrument acts to; open; the valve' 3.5 tot-in? w asel-air outflow. from hecahin and-.tthusdee ereasecabm absolute pressure.

as; lon as the. pr seleotedr ratio: cat-pressures $Xitll it will bev seen tha the control: arm 2"! will hold: the; contact 23; iii-en a ement; withthe ontact-{24x1 and. cont ol: elemem; 49 is precluded fmmeffeeti e: any! contr laotihnon; the; valve 36 which-.wouldtend't sure; @nee-th ratiorofi cabinv a solute press ..9 to.- filehtambrent; pr ssure: dr ps; below theme? eoleeted maximumrvalue. .oontrol arm .21! will-move contaetfli: out i enea em. t with c ntact 24 and the erine fitewi l. hen act, .oclose-thes 551;. at thexsam t mexthae the; cell: 44; s. de eneraired; Thisagain renders the; control means 49 operative to control energization, of the relay .9. .113...

fi ured illustrates: raph; form; in Whieh fiiehtra titude is; lotted. a a nst .nr ssure," alter: forms ofv ur z-schetlu e -rzossible with fihe; cont e144. n: one schedu e; were eated, b Attire eeetrolmeans: 4.9. acts; to hold the; o bin ahso ute Pres ur su st nt lly const nt: af er: the; aircrafthas reached; a tie hee ori -80.9.0 fee ehedu eeahinz bsor ute. pressii e: rernai s.v c nstant at: a, eimul atea l QlREefRIQ HPZQnQ amb en -flin t; p essure w l have equalled; the-pred te m ned d fierential pr ss e ,t-brthe burstin s ren th {lithecabin- 'luheeontrolxaeansfi;w lthereaiter control cabin ..press e: r pre nted by line; Q u st m Qh antunti nal. uele 10,1 a proxim tely -i nr a. l .ed. w ich ime the at cv f u e; pressure o. a bi nt .fli ht pr (Ir-increas c bin a solutemese ill) t-resc edule; re re ented; by .l 3,: ontrol means 49 progressively decreases cabin absolute n ess zet -tme a rc a t: a c d beyond a 5000 f99 %1t tude :unti1 the difrerentiai pressure-l mit area h a- H re ain. h control me s tlwil sow o e ate the v lve as to. mainta n a n dii erenntlalnres ure sub tan ial y constant unt l the. altitude Q. app ox ma e y 30 15 feet is reached: Here again, as in the previously desoribedaschedule; the-amstrumentt of; the: present inuentionwill in' 'eifectsoverride the controllaotion of; the; control) means 49st and so i motivate: the moton-ase-torcontrol operationuofi the valve-"35 to; maintain. thea ratiol of cabinv absolute pressure to; ambientvfiight pressure: at: the preselected value llhiszoontrol'ofi cabin absolute pressureis a ainrrepresented by the: line @131 the graph; of E'ignre; 2;.

It. will. now be: seen: thaothea instrument offzthe present, inventiontiszone which. is: operableingace cmianee: witha selected; ratio 1 of; cabin. absolute measure Ito:ambient;fiightzpressure: and; ismda plreel: to.) cooneratewith; the; valve operatingsvmeans of awmessurezoontroi system;- to-Kso: operatejsaid valreas tolmaintainzthelratio ofacabin absolute messureatot ambient fli ht: pressure substantially coheren at all: altitudes: above/some; datumz. 3113i:- fiueet Elle. control: arm together "with the contacts of! thee instrumen e 0.12 control effecting means a aetee to b eneryatively'; connecteda to thelvfime on rating: meanetora system; such. as; illustrated th siraw 'lheicontrol; efiecting moanstso ior-m iiamotwated': by: the pressure ehangelrepenelre: mqrementaof; theicansule: assembliessto helnaebout: the; desired. control. contents means; utt e: control hereoii.ieeffeetechthreush he fi larm and heteentaetst dherea s no o: be limitee e uhi et' tee ehanaes in he-seepeoi: the eneaeled oontrol air-outrlow remr he ..l .e ernr .eine:: an evacuated housing to be mounted within said cabin; anfirst eansl le; mounted: Within said. housing; means oer 'eei b saidlhousineradanted:to heconnected o: ambient: flight: pressure; ands. communicating Wiifilrt'therint rioreoi saidfirst capsule; a: second @apsula mounteclr'within :saidthousing means-cam ljieekbytsaitk housing adanteditoabe connected to oabmsabsolutezpressuretand oommunicatingwith thfi lnterior. ofssaid.: see.on dcapsule; control efiect' inameans; includingvmeans' adapted-to beaope-rae tlvelyr connected, to; the means rof the. system efieetingrand controlling; outflow of air. from: the

cabin; anclxmeanamotivat-ing saidicontrol effeote 1118;: means through the resultant. movements; of said eepsulesesath isame ovevin re enpressurezanel seonsete tan erin amateur .1 pr ssure; o; decrease; cabin- 3,1336,

bi -IE flight lute pressure-me maintain a'lplteseleetezli ratio: vof cabinabsolute-pressure totambientiflight pressure whenever cabin 1 absolute measure tBIldS5;17Q.. ex: ceedia,value--which producesta: ratioofL-cabin ab solute' pressure I to ambientflight pressure 1 in ex;- cess of'said preselected ratio.

A pressure regulatingrle-vice for use in a system for-regulating pressure within anaircraft cabin, which: system includes an outflow valve controlled by "pressure increasing or pressure de' 7 creasing means of the system, comprising: a housing to be mounted within said cabin; aflrst capsule mounted within said housing responsive solely to changes in cabin absolute pressure; a second capsule mounted within aid housing and responsive solely to changes in ambient flight pressure; control effecting means, including means movably mounted within said housing'and a second means adapted to be operatively connected to the pressure decreasing means of said system, for controlling operation of said decreasing means; means for operatively connecting aid capsules to said movably mounted means whereby said latter means is moved by the conjoint movement of said capsules as the same respond to changes in cabin absolute pressure and ambient flight pressure, respectively, to so motivate said control efiecting means that the latter is adapted to control operation of said pressure decreasing means controlling said outflow valve to decrease cabin absolute pressure whenever the ratio of cabin absolute pressure to flight ambient pressure exceeds a predetermined maximum value.

3. An instrument for use in a system for regulating pressure in an aircraft cabin, which system includes means to effect and control air outflow from the cabin, comprising: a housing to be mounted within said cabin; a first capsule mounted-within said housing and responsive solely to changes in cabin absolute pressure; a second capsule mounted within said housing and responsive solely to changes in ambient flight pressure; control effecting means, including means. movably mounted within said housing and a second means adapted tobe operatively connected to the means of said system for effecting and controlling outflow of air from the cabin; means for operatively connecting said capsules to said movably mounted means whereby said latter means is moved by the conjoint movement of said capsules as said capsules respond to changes in cabin absolute pressure and ambient flight pressure to so motivate said control effecting means that the latter is adapted to control operation of said outflow effecting and controlling a means of said system to vary cabin absolute pressure in accordance with a preselected ratio of cabin absolute pressure to ambient flight pressure.

4. An instrument for use in a system for regulating pressure in an aircraft cabin, which system includes means to effect and controllably increase air outflow from the cabin, comprising: a sealed housing to be mounted within said cabin, said housing internally subject to a substantially constant pressure other than cabin absolute pressure or ambient flight pressure; a first capsule mounted within said housing and responsive to changes in cabin absolute pressure; a second capsule mounted within said housing and responsive to changes in ambient flight pressure; control effecting means, including means adapted to be operatively connected to the means of said system for effecting and controlling increase of outflow of air from the cabin; means operatively connecting said first and second capsules to said control efiecting means whereby the latter is motivated by pressure change responsive movements of said capsules, said capsules being so organized and arranged, whenever the ratio of cabin absolute pressure to ambient flight pressure exceeds a preselected value, to conjointly act to produce such motivation of said control effecting means that the latter is adapted to control operation of said outflow effecting and controlling means of said system to increase airoutflow and thereby decrease cabin absolute pressure to maintain cabin absolute pressure in accordance with said preselected ratio of cabin absolute pressure to ambient flight pressure.

5. A pressure regulating'device for use in' a system for regulating pressure in an aircraft cabin whereinto air is continuously supplied by an air delivery means and including a controllable valve means for regulating air outflow from and hence pressure within said cabin, comprising: an evacuated housing to be mounted within said cabin; a frame removably mounted within said housing; a pair of pressure responsivecapsule assemblies mounted on said frame in a side-by-side rela tionship; means for communicating cabin absolute pressure to the interior of one of said c'ap sule assemblies; means carried by said housing adapted to be connected to ambient flight pres: sure and communicating with the interior of the other of said capsule assemblies; a control arm; means pivotally connecting the movable end of each capsule assembly to said control arm at spaced points therealong whereby said control arm is pivotally moved in response to conjoint movement of said capsule assemblies in response to changes in cabin absolute pressure and ambient flight pressure; and means adapted to be operatively connected to said valve means and including means cooperative with said control arm as it is moved under the conjoint influence of changes in cabin absolute pressure and ambient flight pressure to control operation of said valve means to limit the difference between cabin absolute pressure and ambient flight pressure so that the ratio of cabin absolute pressure to ambient flight pressure is maintained in accordance with a pre determined value.

6. An instrument for use in a system for regulating pressure in an aircraft cabin, which system includes means to effect and control air outflow from the cabin, comprising: an evacuated housing to be mounted within said cabin; a pair of pressure responsive capsule assemblies mounted in a side-by-side relationship within said housing; means for communicating cabin absolute pressure to the interior of one of said cap-- sule assemblies; means for'communicating ambient flight pressure to the interior of the other of said capsule assemblies; a control arm; means for pivotally connecting the movable end of eachcapsule assembly to said control arm at spaced points therealong whereby said control armis pivotally moved in response to the conjoint movement of said capsule assemblies as the latter respond, respectively, to changes in cabin absolute pressure and ambient flight pressure; and means carried by said housing and adapted to be connected to the outflow effecting and controlling means of said system and coacting with said control arm as it is moved by the conjoint resultant movements of said capsule assemblies responding to changes in cabin absolute pressure and ambient flight pressure, respectively, to produce such motivation of said outflow effecting and controlling means of the system to vary cabin absolute pressure in accordance with a preselected ratio of cabin absolute pressure to ambient flight pressure.

7. A pressure regulating device for use in a system for regulating pressure within an aircraft cabin, which system includes an outflow valve controlled by pressure increasing or pressure de-j creasing means of the system, comprising: an evacuated housing to be mounted withinsaid cabin; a first capsule mounted within said housing internally subject to changes in cabin absolute pressure; a second capsule mounted within said housing and internally subject to changes in ambient flight pressure; control effecting means, including means movably mounted within said housing and second means adapted to be operatively connected to the pressure decreasing means of said system, for controlling operation of said decreasing means; means for operatively connecting said capsules to said movably mounted means whereby said latter means is moved by the conjoint movement of said capsules as the same respond to changes in cabin absolute pressure and ambient flight pressure, respectively, to so motivate said control efiecting means that the latter is adapted to control operation of said pressure decreasing means controlling said outflow valve to increase air outflow from said cabin and thereby decrease cabin absolute pressure whenever the ratio of cabin absolute pressure to flight ambient pressure exceeds a predetermined maximum value.

8. An instrument for use in a system for regulating pressure in an aircraft cabin, which system includes means to effect and control air outflow from the cabin, comprising: a housing, internally subject to a pressure other than cabin absolute pressure or ambient flight pressure, to be mounted within said cabin; a first capsule mounted within said housing; means carried by said housing adapted to be connected to ambient flight pressure and communicating with the interior of said first capsule whereby the latter is internally subject to, and movable in response to changes in, ambient flight pressure; a second capsule mounted within said housing; means carried by said housing adapted to be connected to cabin absolute pressure and communicating with the interior of said second capsule whereby the latter is to be internally subject to, and movable in response to changes in, cabin absolute pressure; control eifecting means, including means adapted to be operatively connected to the means of said system for efifecting and controlling outflow of air from the cabin; means operatively connecting said first and second capsules to said control eflecting means whereby the latter is motivated by the conjoint pressure change responsive movements of said capsules, said capsules being so operatively connected to said con trol eiTecting means and being so organized, whenever the ratio of cabin absolute pressure to flight absolute pressure exceeds a preselected value, to produce such motivation of said control effecting means that the latter is adapted to control operation of said outflow eflecting and controlling means of said system to vary cabin absolute pressure in accordance with said preselected ratio 'of cabin absolute pressure to ambient absolute pressure.

9. An instrument for use in a system for regulating pressure in an aircraft cabin, which system includes means to effect and control air outflow from the cabin, comprising: an evacuated housing to be mounted within said cabin; a control arm within said housing; a first capsule mounted within said housing; means carried by said housing adapted to be connected to ambient flight pressure and communicating with the interior of said first capsule whereby the latter is internally subject to, and movable in response to changes in, ambient flight pressure; link means pivotally interconnecting said first capsule and the one end of said control arm; a second capsule mounted within said housing; means carried by said housing adapted to be connected to cabin obsolute pressure and communicating with the interior of said second capsule whereby the latter is to be internally subject to and movable in response to changes in cabin absolute pressure; link means pivotally interconnecting said second capsule and said control arm intermediate the ends thereof, said control arm being motivated by the conjoint pressure change responsive movements of said capsules; and control activating means carried by said housing, including means adapted to be operatively connected to the means of said system for efiecting and controlling outflow of air from the cabin and coacting with said control arm to control operation of said outflow effecting and controlling means in response to a preselected movement of said control arm resulting from pressure change responsive movements of said capsules to produce such motivation of said outflow efiecting and controlling means to vary cabin absolute pressure in accordance with a preselected ratio of cabin absolute pressure to ambient flight pressure.

BRUCE E. DEL MAR.

References Cited in the file of this patent UNITED STATES PATENTS Number I Name Date 2,450,076 Bechberger Sept. 28, 1948 2,549,672 Del Mar Apr. 17, 1951 2,549,690 Klemperer Apr. 17, 1951 2,612,828 Del Mar Oct. 7, 1952 FOREIGN PATENTS Number Country Date 514,055 France Nov. 8, 1920 

